Tenshi, Ei-chan, and Shiratori all attend Kawagoe Academy. One day, they get pulled into the orbit of former conductor Haruo. He drags them into his newly founded boys choir where they suddenly find themselves performing a song in front of an audience!

Breathe in with your stomach
and your back will follow.
استنشقوا من معداتكم، وستتبع ظهوركم
Atmet in den Bauch, 
um die Muskeln dort zu bewegen.
Respiren por el abdomen
y muevan la espalda.
Respirad por el abdomen
y moved la espalda.
Inspirez pour faire bouger
vos abdos,
Se mettete fiato in pancia,
 i muscoli addominali lavorano.
Дышите животом, спина подстроится.